NewJerseyXJ609

Ok for starters I have a 96 Cherokee country with the 4.0 and its auto. I bought it 2 montths ago knowing it needed a brake line... No big deal.. replaced the line ( turned into 3 lines) lol and I hit the road... This is my 4th jeep with the straight 6 so I am fairly familiar... The other day I was heading to work and she shut off at a red light out of nowhere.. towed it home and checked fuel first.. the pump is priming and i have 45 lbs at the rail so it has fuel.. put the tester on it and have no codes at all... Tested for spark and i have none... No power to the coil at all... I know crank sensors are common..... But wou ldn't it.send a code??? This is my DD so i really need to figure this out... Any help would be greatly appreciated... Keep in mind the truck sat for about a year and a half before I bought it....

NewJerseyXJ609

And the truck runs like a top it has 105k miles... That morning that it died on me when i started it at first it cranked and cranked then finally started idled for about 5 seconds than died tried starting it again and it fired up... Drove about 7 miles and that's when it died at the red light... Hasn't started since... Just cranks...

freegdr

have you checked code using key on key off method my 94 just died one day was the cps/pick up coil in dist

freegdr

another thing to check fuse box under hood small fuse going to o2 sensorcrear of tc wires rubbed thru and grounded causing blow fuse think it was in first row in box green

NewJerseyXJ609

On my 95 the key on/off/on/off/on worked... But that was obd1... Since this is obd2 I don't think it will work I hooked it up to 2 different scan tools and both said no codes.... I will take a look at the fuse tho... I took a quick look at them the day it happened and evrything seemed ok...

Kager2002

Sounds like the crank position sensor to me. Mine heats up from time to time when four wheeling. I have a manual so it tends to go out when the clutch heats up. Also a lot of times the exhaust manifold leaks or is cracked and that also heats the cps up and shuts it down. Having no power to the coil is the main symptom of the cps. It's a pain in the a$$ to change those out too, and if you do it your self just be careful not to drop the screw in! (I've heard horror stories.). I've been lucky to have mine come back alive after it heats up, but some of my friends have blown out completely the first time it goes out. Good luck with the fix!

freegdr

thought that started in 97 oops crank sensor would throw code signal lost something someting

NewJerseyXJ609

If the cps is the culprit wouldn't I have a code???

freegdr

should be some thing id think check for spark then fuel yet

NewJerseyXJ609

I have 45 lbs of pressure at the rail... Fuel pump is priming it has fuel.... But like i said I have no spark at all... No power to the coil at all

tjwalker

The absolute primary suspect here IS the crank sensor.

They only set a code about 25% of the time when they fail catastrophically.

They can be tested, but testing is not always conclusive.

If you buy one, do yourself a favor and buy it directly from Jeep for the best reliability and longevity. I answer posts every week about issues with some (not all) aftermarket crank sensor. Mopar unit is well worth the extra money.

Kager2002

Here is a good write up:


Troubleshoot and test, before you buy new parts.

The CPS is the most common failure, but not the only one that can cause a no-start.



The most likely cause of it cranks and cranks but won't start up is the Crankshaft Position Sensor (CPS) located on the transmission bell housing. Often this part is also referred to as the CranKshaft Position Sensor (CKP) CPS/CKP failure is very common. The CPS/CKP can stop working with no warning or symptoms and the engine will not run or the engine may randomly stall for no apparent reason.

Crank Position Sensors can have intermittent "thermal failure". This means that the CPS/CKP fails when engine gets hot, but works again (and will test as "good") when it cools back down.

Begin with basic trouble shooting of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. Jeeps do not tolerate low voltage or poor grounds and the ECM/ECU may behave oddly until you remedy this.



Symptoms -
- Starter cranks and cranks but engine won't start up and run.
- Fuel gauge and voltage gauge may not work or display properly.
- You sometimes will have No Bus on the odometer after 30-60 seconds.
- A failed CPS/CKP may or may not throw a CEL trouble code.
- No spark at the spark plugs.
- Fuel pump should run and prime for 3-5 seconds.

If the CPS/CKP is failed sometimes the OBD-II trouble code reader cannot make a connection to the ECU/computer or cannot read Check Engine Light/MIL codes because the CPS/CKP has failed. Disconnect the code reader, disconnect the CPS/CKP wire connector, and reconnect the code reader. If the code reader establishes contact with the ECU and scans, your CPS/CKP is failed and needs to be replaced.


Diagnostic steps to confirm the CPS is the cause of your no-start


You should be able to verify a bad cps, by unplugging it, and turning the ignition key to on. If the voltage gauge and/or the fuel gauge now displays correctly, replace the CPS.

Unplugging and reconnecting the CPS sensor where it connect to the main harness near the back of the intake manifold usually resets the ECU and if the jeep fires right up after doing this you can bet that the CPS is faulty and needs to be replaced.

Exchange the fuel pump relay and the ASD relay with one of the other similar ones in the PDC to eliminate the relays as the cause of the no-start. Confirm that the fuel pump to runs for 3-5 seconds when you turn the ignition key to ON.

Eliminate the NSS as a cause of no start. Wiggle the shift lever at the same time you try to start. Put the transmission in Neutral and do the same. Do the reverse lights come on when the shifter is in Reverse?

Inspect the wires and wire connectors at the O2 sensors on the exhausts pipe. A short circuit from melted insulation or from broken O2 sensor wires can blow a fuse and the ECU/ECM will loose communication. Don't get tunnel vision and assume the sensor is bad (unless it tests bad with a meter). Damaged wiring or a dirty connector can inhibit the signal from making it to the computer. Inspect/test/clean/repair wiring or connectors as necessary.


CPS Testing


Crankshaft Position Sensor Connector (CPS/CKP)



.



TESTING PROCEDURE 1991 - 2001 4.0L H.O. engines

1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

TESTING PROCECURE for 1987 - 1990 4.0 L engines

Test # 1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the CPS and measure across the CPS connector's A & B leads. Your meter should show a CPS resistance of between 125 - 275 Ohms. . If the CPS is out of that range by much, replace it.

Test # 2 - You'll need a helper for this one. Set the volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your helper cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.


The 2000 and 2001 will have the CPS in the same location on the bell housing, but the wire connector may be on the passenger side, not as shown in the diagram below. Simply follow the wire from the sensor to the connector.

.

NewJerseyXJ609

Little update... I took an ecm from a 97 and put it in and it fired up.. ran for 10 mins I then shut it off and fired it back up... No problem then as I was walking in the garage to grab a scan tool it shut off it fired back up ran for 3 seconds and then never started again... I then put the original Edna back in and it wouldn't start... When cranking it has power to the coil for about 2 seconds then nothing.... I think I'm gonna try the cps next but tell me what you guys think about that.... Lol

NewJerseyXJ609

To eveyone replying thank you so much for your input... I appreciate any help in this situation... Haha

nickxj94

its either the cps or the coil replace cps first tho thats always the culprit on my 94xj get one from mopar or "dodge" they seem to be better i been through 5 of the oreially ones lol there lifetime but its getting old next im buying one from dodge